Producer's Muppet mishap led to cut cameo

During one ensemble scene in the highly-anticipated return of Jim Henson's colourful characters, extra puppeteers were needed, and Lieberman jumped at the chance to control one of the beloved bunch.

But after reviewing his guest appearance, the moviemaker realised his muppet was lacking star quality - and he had to cut it out of the film.

He says, "I learned how difficult it really is. You're sweating, your arm hurts. Then, in post-production, the visual effects supervisor noticed there was one Muppet in the scene that looked totally wrong. It was angled weird. It had no reaction. It was totally off. Guess what? It was my Muppet. And it got cut out."